Distinguish the toxic differentiations between acute exposure of micro- and nano-plastics on bivalves: An integrated study based on transcriptomic sequencing

Plastic pollution represents one of the most severe marine environmental issues today. In the present study, mussel Mytilus coruscus, was selected as the model organism to probe the toxic effects of acute exposure to different sizes of plastic particles using integrated transcriptomic techniques and histological and biochemical analysis. Nanoplastics (NPs) were efficiently ingested by mussels, thereby inducing a severe inflammatory response. Although no distinct aggregation of microplastics (MPs) was observed, a slight inflammatory response has still occurred. Biochemical analysis revealed a significant up-regulation of biomarkers after exposure to plastic particles. Further, NPs caused more ROS production and higher T-AOC level than MPs. Transcriptomic sequencing was performed, and these differentially expressed genes after MNPs exposure were mostly enriched in pathways involved in stress and immune response. Notably, a contrast expression, substantial upregulation in MPs treatment and downregulation in NPs treatment of specific genes include in these pathways were revealed. Collectively, these results indicated that acute exposure to NPs is more toxic than MPs. Additionally, MPs exposure perhaps caused the impairment of olfactory function and neurotoxicity to mussels. These data provided some new clues for the elucidating of ecotoxicological mechanisms underlying plastic particles exposure.

Automated summary

Plastic pollution is a severe marine environmental issue. This study investigated the toxic effects of acute exposure to different sizes of plastic particles on mussels using various techniques. The results showed that mussels efficiently ingested nanoplastics and experienced a severe inflammatory response, while microplastics caused a slight inflammatory response. Biochemical analysis revealed up-regulation of biomarkers after plastic particle exposure. Nanoplastics induced more ROS production and higher T-AOC level than microplastics. Transcriptomic sequencing indicated that differentially expressed genes were mostly involved in stress and immune response pathways. Acute exposure to nanoplastics was found to be more toxic than microplastics. Microplastics exposure may impair olfactory function and cause neurotoxicity to mussels. These findings provide new insights into the ecotoxicological mechanisms of plastic particle exposure.